(a) Field of the Invention
The present invention relates to a liquid crystal display and a driving method thereof.
(b) Description of the Related Art
A liquid crystal display (“LCD”) is one of the most widely used types of flat panel displays (“FPD”), and it is typically composed of two display panels on which field generating electrodes such as pixel electrodes and a common electrode are formed, and a liquid crystal layer interposed between the two display panels. Voltages are applied to the field generating electrodes to generate an electric field within the liquid crystal layer, and the alignment of liquid crystal molecules of the liquid crystal layer is determined by the electric field. Accordingly, the polarization of incident light is controlled, thereby performing image display.
The LCD is typically driven through polarity inversion in which the polarity of the voltage applied to the liquid crystal layer is changed after each frame to prevent the degradation of the liquid crystal layer. The inversion driving may be applied in various ways such as by pixel unit, by pixel row unit, and by pixel column unit.
Also, the liquid crystal layer is arranged according to an electric field generated by an electrode applied with a predetermined voltage level and an electrode applied with a different voltage every frame. In such an LCD, the magnitude of the voltage applied to one electrode must be large, and to eliminate this problem, a driving method in which two electrodes are applied with different voltages per frame has been proposed.
In such a driving method, the voltages applied to two electrodes are changed every frame, however the charges may be irregularly accumulated within the two electrodes over a long operational time, and as a result, an electric field is generated between the two electrodes such that the liquid crystal layer is arranged in an arbitrary direction such that leakage light and afterimages may be generated.